One of the goals of semiconductor electronics is the attainment of higher and higher operating speeds. For these high speed operations, integrated circuits having bipolar transistors are typically used. These digital circuits have transistors which switch from one state to another. Unless some special arrangements are made, these critical switching transistors often go into a saturation mode. In this mode the number of minority carriers is so great within regions of the transistor that the switching time of the transistor is slowed.
One arrangement to prevent saturation is to couple Schottky diodes to the switching transistors. However, this solution requires special steps in many integrated circuit manufacturing processes, such as processes using P type epitaxial layers for the base region of the transistors or processes using polysilicon electrode contacts.
Other arrangements avoiding Schottky diodes are circuit designs requiring no diodes or requiring standard integrated circuit diodes. However, these efforts have not been entirely successful. In integrated semiconductor memory circuits the READ time, the time in which a bit of information is retrieved from a memory cell, and the WRITE time, the time in which a bit of information is stored in a memory cell, have not been as fast as desired in many applications, such as in high speed computers.
The present invention reaches many of the goals of high speed operation, but without the use of Schottky diodes. Instead standard integrated circuit diodes are used requiring no special processing steps. Furthermore, the present invention provides for a memory system having a high density since the basic memory cell which forms the memory array is very compact in size.